Mast cell activation in arthritis: detection of alpha- and beta-tryptase, histamine and eosinophil cationic protein in synovial fluid

1. Although mast cell hyperplasia is a feature of rheumatoid arthritis and osteoarthritis, the extent and nature of mast cell activation in joint disease have not been clearly established. 2. We have investigated the levels of mast cell tryptase and histamine and also of eosinophil cationic protein in synovial fluid collected from 31 patients with rheumatoid arthritis, 14 with seronegative spondyloarthritis and nine with osteoarthritis. Two RIAs for tryptase were employed: one with monoclonal antibody AA5, which was found to bind equally well to both alpha and beta isoforms on Western blots of the recombinant enzyme, and the other with antibody G5, which recognizes predominantly beta-tryptase. 3. alpha-Tryptase, which is likely to be released constitutively from mast cells, appeared to be the major form in synovial fluid, as the assay with antibody AA5 detected appreciably more tryptase than that with antibody G5. beta-Tryptase, which is released on anaphylactic activation of mast cells, was detected in 14 out of 45 synovial fluid samples studied, with concentrations of up to 12 micrograms/l measured by the G5 assay. The apparent levels of beta-tryptase, but not of alpha-tryptase, were closely correlated with those of histamine in the synovial fluid. Patients with osteoarthritis appeared to have a greater proportion of beta-tryptase in the synovial fluid than those with rheumatoid arthritis, as well as higher concentrations of histamine. Eosinophil cationic protein was present at high levels in the synovial fluid, although eosinophil numbers were low, and its concentrations were not correlated with the concentrations of the mast cell products. 4. These data suggest that anaphylactic degranulation of mast cells may have occurred to a greater extent in osteoarthritis than in rheumatoid arthritis, despite the relative lack of synovial inflammation in osteoarthritis. Although the eosinophil cationic protein detected may not reflect eosinophilic inflammation in the joint, the presence in synovial fluid of tryptase of both major forms, and of histamine, appears to indicate that mast cell products are secreted constitutively, as well as by processes of anaphylactic degranulation in rheumatoid arthritis, seronegative spondyloarthritis and osteoarthritis.

Human tryptase fibrinogenolysis is optimal at acidic pH and generates anticoagulant fragments in the presence of the anti-tryptase monoclonal antibody B12

Human tryptase is uniquely regulated by its association with heparin and resists inhibition by biological protease inhibitors. The effects of pH and B12, an IgG anti-tryptase mAb, on cleavage of the synthetic substrate tosyl-Gly-Pro-Lys-p-nitroanilide and of the biological substrate fibrinogen by tryptase were examined. Tosyl-Gly-Pro-Lys-pnitroanilide cleavage was optimal at neutral pH and was inhibited by the B12 mAb at acidic and neutral pH values. At pH 7.5, inhibition was reversible and noncompetitive. In contrast, the optimal pH for tryptase to cleave fibrinogen was acidic. B12 dramatically enhanced the rate and extent that tryptase cleaved all three fibrinogen subunits at pH 6.0 to 6.5, but inhibited these activities at neutral pH. Major fibrinogen cleavage fragments generated at acidic pH by the B12:tryptase complex were identical with those made by plasmin. Thus, at acid pH, tryptase alone destroyed the ability of fibrinogen to clot, while the B12:tryptase complex increased the rate of fibrinogenolysis and also generated the anticoagulant, fragment D. The acidic pH optimum for tryptase fibrinogenolysis may direct this activity to tissue sites of inflammation. A putative biological equivalent to B12 would limit tryptase fibrinogenolytic activity at sites of neutral pH, such as blood, but would augment activity at acidic sites.

Oxidation of cyclophosphamide to 4-hydroxycyclophosphamide and deschloroethylcyclophosphamide in human liver microsomes

We have investigated the formation of 4-hydroxycyclophosphamide (HCY) and deschloroethylcyclophosphamide (DCCY) from cyclophosphamide (CY) in human liver microsomes. For HCY, the estimated values (mean +/- SD; n = 3) of Km1 and Km2 were 0.095 +/- 0.072 and 5.09 +/- 4.30 mM, and the estimated values of Vmax1 and Vmax2 were 0.138 +/- 0.070 and 1.55 +/- 0.50 nmol/min/mg protein. For DCCY, Km1 and Km2 were 0.046 +/- 0.017 and 8.58 +/- 5.84 mM, and Vmax1 and Vmax2 were 0.006 +/- 0.003 and 0.274 +/- 0.214 nmol/min/mg protein. At CY concentrations of 0.1, 0.7, and 5 mM, HCY respectively accounted for 95.7 +/- 1.3, 95.1 +/- 2.4, and 90.7 +/- 2.7% of the total products of CY (HCY + DCCY; n = 6). In a separate experiment, 98.7 +/- 11.9% (n = 3) of CY loss could be accounted for by the formation of HCY at 0.1 mM CY. On the basis of cytochrome P450 (CYP) isoform-specific chemical inhibitor and cDNA-expressed human P450 isozyme studies, CYP2C9 and CYP3A4/5 seemed to be the major P450 isoforms responsible for HCY formation at low (0.1 mM) and high (0.7 and 5 mM) concentrations of CY, respectively. Although orphenadrine inhibition was observed in human liver microsomes (which has been taken to indicate CYP2B6 catalysis), orphenadrine inhibited cDNA-expressed CYP3A4 formation of HCY to the same extent observed in human liver microsomes, and the addition of orphenadrine to incubations containing sulfaphenazole (a specific inhibitor of CYP2C9) or troleandomycin (a specific CYP3A inhibitor) did not increase inhibition beyond that observed with sulfaphenazole or troleandomycin alone. Similar studies indicated that CYP3A4/5 was the major P450 isoform responsible for DCCY formation at high (0.7 and 5 mM) concentrations of CY. The P450 isoform responsible for DCCY formation at 0.1 mM CY could not be identified due to its very low formation rate.

[The prospective study of the influence of cytomegalovirus (CMV) infection of pregnant women to fetus]

Screening of CMV infection in 450 pregnant women in Shenyang was carried on by ELISA and PCR methods, and CMV infection was detected in 100 of their infants prospectively. The results were 97.11% of pregnant women with past infection, 0.89% with primary infection, 11.11% with recurrent infection, only 2% were susceptible. From 450 pregnant women, there were 3 infants with congenital defects and 3 abortions in active infective group, who were positive for IgM antibody, CMV DNA were positive in heparin peripheral blood, cervical secretion, placenta or amnionic fluid. The fetal infection rate and congenital defect rate in infective group were higher than that in inactive control group. Within 100 maternal-infant pair group, congenitally infected infants were 1.43 times higher in infective group than that in control group (RR = 1.43). Two infants with mental retardations (MDI<70) were born in infective group, but none in control group. In our study, primary infection of early pregnancy was most harmful to fetus, the intrauterine transmission rate was 33.3%. Among nine infected infants born from the infective group, two infants were with CID, and seven were symptomless. CMV screening is important for pregnant women in view of eugenic. When active CMV infection is found in early pregnancy, termination of pregnancy is better considered while CMV detection of amniotic fluid is also positive.

Human mast cells stimulate vascular tube formation. Tryptase is a novel, potent angiogenic factor

The presence of mast cells near capillary sprouting sites suggests an association between mast cells and angiogenesis. However, the role of mast cells in blood vessel development remains to be defined. In an attempt to elucidate this relationship, we investigated the effect of human mast cells (HMC-1) and their products on human dermal microvascular endothelial cell (HDMEC) tube formation. Coculture of HMC-1 with HDMEC led to a dose-response increase in the network area of vascular tube growth. Moreover, the extent of neovascularization was enhanced greatly when HMC-1 were degranulated in the presence of HDMEC. Further examination using antagonists to various mast cell products revealed a blunted response (73-88% decrease) in the area of vascular tube formation if specific inhibitors of tryptase were present. Tryptase (3 microg/ml) directly added to HDMEC caused a significant augmentation of capillary growth, which was suppressed by specific tryptase inhibitors. Tryptase also directly induced cell proliferation of HDMEC in a dose-dependent fashion (2 pM-2 nM). Our results suggest that mast cells act at sites of new vessel formation by secreting tryptase, which then functions as a potent and previously unrecognized angiogenic factor.

Human mast cells activate fibroblasts: tryptase is a fibrogenic factor stimulating collagen messenger ribonucleic acid synthesis and fibroblast chemotaxis

The effect of human mast cells on fibroblast activity was studied using an organotypic skin-equivalent culture system. Human mast cell-1 (HMC-1) cells were embedded in a collagen gel with neonatal dermal fibroblasts at a ratio of 1:4; keratinocytes then were allowed to stratify above this composite culture. Analysis of type a1(I) procollagen mRNA synthesis by in situ hybridization revealed a substantial increase in mRNA levels in the presence of mast cells and especially following degranulation, induced by calcium ionophore A23187. Tryptase, a major product of human mast cells, could substitute for mast cells in this culture system, up-regulating procollagen mRNA synthesis. Tryptase pretreated with the specific protease inhibitor bis(5-amidino-2-benzimidazo-lyl)methane (BABIM) markedly attenuated the collagen mRNA up-regulation. Further studies revealed HMC-1 cell sonicates stimulated fibroblast chemotaxis and procollagen mRNA synthesis. Inhibition of HMC-1 sonicates with either BABIM or a neutralizing mAb against tryptase resulted in significant reduction of fibroblast chemotaxis and procollagen mRNA, implying that tryptase accounted for the majority of HMC-1 sonicate activity. Tryptase directly stimulated fibroblast chemotaxis with optimal concentrations between 10 pM and 1 nM. The maximal response of optimal concentrations of tryptase was comparable with the known fibrogenic factor, TGF-beta. Inhibition of tryptase with BABIM resulted in approximately 50% reduction in chemotactic activity. Additional studies revealed that tryptase (0.3-3 nM) stimulated procollagen mRNA synthesis in confluent monolayers of dermal fibroblasts.

Inhibition by hirulog-1 of generation of plasminogen activator inhibitor-1 from vascular smooth-muscle cells induced by thrombin

Hirulog-1 effectively prevents thrombosis in coronary artery disease and is associated with a low incidence of bleeding complications. Our study characterized the effect of Hirulog-1 on thrombin-induced production of plasminogen activator inhibitor-1 (PAI-1) in cultured baboon aortic smooth-muscle cells (BASMCs). Thrombin increased the steady-state levels of PAI-1 messenger RNA (mRNA) and the release of PAI-1 antigen from BASMCs. Treatments with 10-20 mg/L of Hirulog-1 inhibited >80% of thrombin-induced PAI-1 generation from BASMCs. Hirulog-1 alone did not significantly alter PAI-1 production in the absence of thrombin. Significant reduction of thrombin-induced PAI-1 release was observed in cultures treated with Hirulog-1 for 1 h. The maximal effect of Hirulog-1 on thrombin-induced PAI-1 release was achieved in cultures treated with thrombin plus Hirulog-1 for 3 to 6 h, associated with the normalization of PAI-1 mRNA levels induced by thrombin treatment. Strong inhibition by Hirulog-1 on thrombin-induced PAI-1 release remained in cultures with 8 h of the treatment, but the effect was attenuated 16 h after a single addition of the inhibitor. Our study demonstrates that Hirulog-1 effectively inhibited thrombin-induced PAI-1 production in cultured vascular SMCs at mRNA and protein levels. Vascular SMCs may be exposed to high concentrations of thrombin when endothelium is injured. The information generated from this study suggests that Hirulog-1 potentially prevents intravascular thrombogenesis through inhibiting thrombin-induced PAI-1 production in vascular SMCs, especially when hypercoagulation and endothelial injury occurs.

G proteins and phospholipase C mediate thrombin-induced generation of plasminogen activator inhibitor-1 from vascular smooth muscle cells

The present study investigated transcellular signalling mechanism involved in thrombin-induced production of plasminogen activator inhibitor-1 (PAI-1) in cultured vascular baboon aortic smooth muscle cells (BASMC). Treatments with thrombin dose-dependently increased the steady state levels of PAI-1 mRNA and the generation of PAI-1 antigen from BASMC. Thrombin receptor-activating peptide mimicked the effect of thrombin on the generation of PAI-1. Sodium fluoride (1 mM) stimulated PAI-1 generation from BASMC. Pertussis toxin dose-dependently suppressed thrombin-induced increase of PAI-1 generation. Treatment with 5 mM neomycin, 10 microM U73122 or 1 microM calphostin C blocked thrombin-induced PAI-1 generation. Phorbol myristate acetate at 10 nM for 3 h strongly stimulated the generation of PAI-1 from BASMC. Forskolin (100 microM) or 8-bromo-cAMP (100 microM) suppressed thrombin-induced PAI-1 generation. The responses of quiescent BASMC to thrombin or the inhibitors on PAI-1 generation were comparable to that of growing cells. The results of the present study suggest that pertussis toxin-sensitive G proteins and a phospholipase C are involved in thrombin-induced generation of PAI-1 in BASMC, which may transmit signals from occupied thrombin receptor to protein kinase C and thereby increase the generation of PAI-1. Elevated levels of intracellular cAMP may negatively regulate the generation of PAI-1 from vascular SMC.

Human mast cells activate fibroblasts: tryptase is a fibrogenic factor stimulating collagen messenger ribonucleic acid synthesis and fibroblast chemotaxis

The effect of human mast cells on fibroblast activity was studied using an organotypic skin-equivalent culture system. Human mast cell-1 (HMC-1) cells were embedded in a collagen gel with neonatal dermal fibroblasts at a ratio of 1:4; keratinocytes then were allowed to stratify above this composite culture. Analysis of type a1(I) procollagen mRNA synthesis by in situ hybridization revealed a substantial increase in mRNA levels in the presence of mast cells and especially following degranulation, induced by calcium ionophore A23187. Tryptase, a major product of human mast cells, could substitute for mast cells in this culture system, up-regulating procollagen mRNA synthesis. Tryptase pretreated with the specific protease inhibitor bis(5-amidino-2-benzimidazo-lyl)methane (BABIM) markedly attenuated the collagen mRNA up-regulation. Further studies revealed HMC-1 cell sonicates stimulated fibroblast chemotaxis and procollagen mRNA synthesis. Inhibition of HMC-1 sonicates with either BABIM or a neutralizing mAb against tryptase resulted in significant reduction of fibroblast chemotaxis and procollagen mRNA, implying that tryptase accounted for the majority of HMC-1 sonicate activity. Tryptase directly stimulated fibroblast chemotaxis with optimal concentrations between 10 pM and 1 nM. The maximal response of optimal concentrations of tryptase was comparable with the known fibrogenic factor, TGF-beta. Inhibition of tryptase with BABIM resulted in approximately 50% reduction in chemotactic activity. Additional studies revealed that tryptase (0.3-3 nM) stimulated procollagen mRNA synthesis in confluent monolayers of dermal fibroblasts.

Oxidative modification enhances lipoprotein(a)-induced overproduction of plasminogen activator inhibitor-1 in cultured vascular endothelial cells

Elevated levels of plasma lipoprotein (a) [Lp(a)] have been considered as a strong risk factor for premature cardiovascular diseases. Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of plasminogen activators (PA). Increases in PAI-1 levels with or without a reduction in PA levels have been frequently found in coronary artery disease patients. The present paper examined the effects of oxidized Lp(a) on the production of PAI-1 in cultured human umbilical vein endothelial cells (HUVEC). Lp(a) and Lp(a)-free, low density lipoprotein (LDL) were prepared using lysine-Sepharose 4B affinity chromatography. Incubations with 10(-8) M levels of native Lp(a) moderately increased the levels of biologically active PAI-1 in post-culture medium of HUVEC compared to that with equimolar concentrations of native Lp(a)-free LDL. The release of PAI-1 induced by Lp(a) was enhanced by oxidative modification with copper ion. The stimulation of oxidized Lp(a) on PAI-1 production reached plateau in EC treated with 10-20 nM oxidized Lp(a) modified by microM CuSO4. Treatment with 0.2 micrograms/ml of actinomycin D significantly reduced native and oxidized Lp(a)-induced PAI-1 overproduction in EC. Increases in the steady state levels of PAI-1 mRNA were detected in native or oxidized Lp(a)-treated EC. The effect of Lp(a)-free oxidized LDL on PAI-1 production was significantly weaker than the equimolar amount of oxidized Lp(a) but stronger than that of native LDL. Treatments with oxidized Lp(a) increased cell-associated PAI-1 to a similar extent as that in native Lp(a)-treated EC. The results of the present paper demonstrate that oxidative modification enhances Lp(a)-induced PAI-1 production in vascular endothelial cells at RNA transcription level, which suggests that oxidization potentially amplifies the anti-fibrinolytic and thrombotic effect of Lp(a).

Physicochemical basis of the universal genetic codes--quantitative analysis

Quantitative mathematic models have been developed to correlate the fragment hydrophobicity contribution constants (faa) of 20 amino acids with the physicochemical properties (mu, Hb, and square root of MW) of the four bases (U, A, C, G) of the codons, or those of the anticodons. Using the general equation faa = a mu 1 + b mu 2 + c mu 3 + d square root of MW1 + e square root of MW2 + f square root of MW3 + g Hb1 + h Hb2 + i Hb3 + j, where 1, 2, 3 refer to the first, the second and the third base respectively, correlation coefficient of about 0.82 can be obtained for all 20 amino acids coded by 61 different triplet codes. These correlations are statistically highly significant, even though they do not take into account the involvement of various factors and peptidyl transferases. Furthermore, the reasons for the three stop codons are revealed. The graphic presentation of the codons and the amino acids coded separates the acidic and the basic, the aromatic and the heterocyclic amino acids into different quadrants of an octagon. This is in agreement with the ancient Chinese Ying-Yang theory embedded in the classical I-Ching.

Natural products and their derivatives as cancer chemopreventive agents

This review summarizes currently available data on the chemopreventive efficacies, proposed mechanisms of action and relationships between activities and structures of natural products like vitamin D, calcium, dehydroepidandrosterone, coenzyme Q10, celery seed oil, parsley leaf oil, sulforaphane, isoflavonoids, lignans, protease inhibitors, tea polyphenols, curcumin, and polysaccharides from Acanthopanax genus.

Expression of rat liver tryptophan 2,3-dioxygenase in Escherichia coli: structural and functional characterization of the purified enzyme

The hepatic hemoprotein tryptophan 2,3-dioxygenase (TDO) is the key regulatory enzyme that, through irreversible degradation, controls the flux of tryptophan through physiologically relevant pathways. This enzyme is composed of four identical subunits and in its fully assembled tetrameric form requires 2 mol of heme (Fe(+2)-protoporphyrin IX)/mol of protein for functional competence. Using a full-length cDNA for the rat liver TDO subunit (pUC119/TDO) as the template, TDO cDNA was amplified by polymerase chain reaction (PCR) and incorporated into the expression vector pTrc99A after introduction of convenient restriction sites as well as modification of the second codon AGT to GCT to optimize its bacterial expression. DH5 alpha F' strain Escherichia coli cells transfected with this pTrc99A/TDO construct expressed soluble, functionally active, tetrameric TDO protein in high yields. The enzyme was isolated from 30,000g supernatant of cell lysates, purified by ion-exchange chromatography, and its spectral and catalytic properties were assessed in terms of its substrate and prosthetic moiety specificities. In almost all aspects, the bacterially expressed enzyme was found to be identical to that of the rat liver. Heterologous expression of the fully functional enzyme, we trust, will enable future elucidation of its structure-function relationships.

[The study of clinical pathology on bronchial hyperresponsiveness]

OBJECTIVE

To study mechanism of bronchial hyperresponsiveness (BHR) and the relationship between asymptomatic BHR and asthma.

METHODS

Bronchial biopsies were taken through fiberoptic bronchoscope from 17 cases of asymptomatic BHR, 12 cases of chronic asthma with remission and 10 normal control subjects. Bronchial mucosas were investigated by light microscopy and transmission electron microscope. Analysed by morphometric technique for the granules in both eosinophils (EOS) and mast cells (MC).

RESULTS

Airway allergic inflammation (AAI) existed in 9 cases (53%) with asymptomatic BHR. It was similar in bronchial mucosal pathologic changes to chronic asthma with remission. Inflammation existed in the other 8 cases (47%), but unlike AAI, there were no infiltration of EOS and MC in bronchial mucosa.

CONCLUSIONS

The pathological changes of asthma in bronchial mucosa were existed in a part of patients with asymptomatic BHR.

Production of genetically stable high-titer retroviral vectors that carry a human gamma-globin gene under the control of the alpha-globin locus control region

The ability to generate stable high-titer vectors that give rise to high levels of expression of transduced globin genes in erythroid cells is a prerequisite for effective retroviral-mediated globin gene therapy. The human beta-globin gene with its immediate flanking sequences does not contain all the regulatory elements necessary for regulated high-level and position-independent expression in erythroid cells. The regulatory element known as the beta-globin locus control region (BetaLCR) can provide a linked Beta-globin gene with these properties. However, addition of BetaLCR sequences to a retrovirus carrying a beta-globin gene increases its genetic instability. We have developed a new generation of retroviral vectors in which a human gamma-globin gene is placed under the control of the alphaLCR, the major regulatory element of the alpha-globin gene cluster. We demonstrate that these retroviruses are genetically stable in producer cell lines and can be produced at high titers that exceed 5 x 10(6) colony-forming units (CFU)/mL. In addition, we show that the transduced gamma-globin gene can be expressed in the adult erythroid environment of mouse erythroleukemia (MEL) cells at a level comparable to that of a single endogenous Betamaj-globin gene. These retroviruses can also transduce primary murine bone marrow progenitor cells as efficiently as retroviruses that carry the neomycin resistance (neor) gene. This new generation of globin retroviral vectors may prove useful for gene therapy of human beta-globin gene disorders such as sickle cell disease and beta-thalassemia.

A novel heparin-dependent processing pathway for human tryptase. Autocatalysis followed by activation with dipeptidyl peptidase I

Tryptase is the major protein constituent of human mast cells, where it is stored within the secretory granules as a fully active tetramer. Two tryptase genes (alpha and beta) are expressed by human mast cells at the level of mRNA and protein, each with a 30 amino acid leader sequence. Recombinant precursor forms of human alpha- and beta-tryptase were produced in a baculovirus system, purified, and used to study their processing. Monomeric beta-protryptase first is shown to be intermolecularly autoprocessed to monomeric beta-pro'tryptase at acid pH in the presence of heparin by cleavage between Arg-3 and Val-2 in the leader peptide. The precursor of alpha-tryptase has an Arg-3 to Gln-3 mutation that precludes autoprocessing. this may explain why alpha-tryptase is not stored in secretory granules, but instead is constitutively secreted by mast cells and is the predominant form of tryptase found in blood in both healthy subjects and those with systemic mastocytosis under nonacute conditions. Second, the NH2-terminal activation dipeptide on beta-pro'tryptase is removed by dipeptidyl peptidase I at acid pH in the absence of heparin to yield an inactive monomeric form of tryptase. Conversion of the catalytic portion of beta-tryptase to the active homotetramer at acid pH requires heparin. Thus, beta-tryptase homotetramers probably account for active enzyme detected in vivo. Also, processing of tryptase to an active form should occur optimally only in cells that coexpress heparin proteoglycan, restricting this pathway to a mast cell lineage.

CACCC and GATA-1 sequences make the constitutively expressed alpha-globin gene erythroid-responsive in mouse erythroleukemia cells

Although the human alpha-globin and beta-globin genes are co-regulated in adult life, they achieve the same end by very different mechanisms. For example, a transfected beta-globin gene is expressed in an inducible manner in mouse erythroleukemia (MEL) cells while a transfected alpha-globin gene is constitutively expressed at a high level in induced and uninduced MEL cells. Interestingly, when the alpha-globin gene is transferred into MEL cells as part of human chromosome 16, it is appropriately expressed in an inducible manner. We explored the basis for the lack of erythroid-responsiveness of the proximal regulatory elements of the human alpha-globin gene. Since the alpha-globin gene is the only functional human globin gene that lacks CACCC and GATA-1 motifs, we asked whether their addition to the alpha-globin promoter would make the gene erythroid-responsive in MEL cells. The addition of each of these binding sites to the alpha-globin promoter separately did not result in inducibility in MEL cells. However, when both sites were added together, the alpha-globin gene became inducible in MEL cells. This suggests that erythroid non-responsiveness of the alpha-globin gene results from the lack of erythroid binding sites and is not necessarily a function of the constitutively active, GC rich promoter.

QSAR analysis of membrane permeability to organic compounds

A general mathematical model involving partition coefficient, molecular weight and hydrogen bonding is used to correlate the structures and permeability of various organic compounds through the toad urinary bladder and human red blood cell (RBC) membranes. Log Per (permeability) is correlated with log Po/w (partition coefficient in olive oil/water, or ether/water), log MW (molecular weight) and Hb (hydrogen bonds). Log Po/w is the most important factor among three parameters examined. While increased MW always has a negative effect on the permeability, increased Hb can have either a slightly positive or a slightly negative effect depending on the solvent and membrane systems used. Systematic comparison of the QSAR's (quantitative structure activity relationship) of different biological membranes may serve as a useful guide in drug targeting to different tissues and cell types.

The alpha form of human tryptase is the predominant type present in blood at baseline in normal subjects and is elevated in those with systemic mastocytosis

Tryptase, a protease produced by all mast cells, was evaluated as a clinical marker of systemic mastocytosis. Two sandwich immunoassays were evaluated, one which used the mAb G5 for capture, the other which used B12 for capture. The B12 capture assay measured both recombinant alpha- and beta-tryptase, whereas the G5 capture assay measured primarily recombinant beta-tryptase. G5 binds with low affinity to both recombinant alpha-tryptase and tryptase in blood from normal and nonacute mastocytosis subjects, and binds with high affinity to recombinant beta-tryptase, tryptase in serum during anaphylaxis, and tryptase stored in mast cell secretory granules. B12 recognizes all of these forms of tryptase with high affinity. As reported previously, during systemic anaphylaxis in patients without known mastocytosis, the ratio of B12- to G5-measured tryptase was always < 5 and approached unity (Schwartz L.B., T.R. Bradford, C. Rouse, A.-M. Irani, G. Rasp, J.K. Van der Zwan and P.-W.G. Van der Linden, J. Clin. Immunol. 14:190-204). In this report, most mastocytosis patients with systemic disease have B12-measured tryptase levels that are elevated (> 20 ng/ml) and are at least 10-fold greater than the corresponding G5-measured tryptase level. Most of those subjects with B12-measured tryptase levels of < 20 ng/ml had only cutaneous manifestations. The B12 assay for alpha-tryptase and beta-tryptase, particularly when performed in conjunction with the G5 assay for beta-tryptase, provides a more precise measure of mast cell involvement than currently available assessments, a promising potential screening test for systemic mastocytosis and may provide an improved means to follow disease progression and response to therapy.

Analysis of the antibody response to immunization with purified O-acetyl GD3 gangliosides in patients with malignant melanoma

Gangliosides expressed in malignant melanoma are potential targets for immunotherapy. Immunization of melanoma patients with vaccines containing purified GM2 ganglioside has resulted in induction of GM2 antibodies, and high titers of GM2 antibodies have correlated with increased survival. Melanoma ganglioside 9-O-acetyl GD3 is another candidate for ganglioside vaccine construction because of its limited expression in normal human tissues. As purification of 9-O-acetyl GD3 from human melanoma (9-O-acetylated on the terminal sialic acid) is not practical for broad application, we investigated the antibody response of melanoma patients to O-acetyl GD3 from several additional sources: hamster melanoma (7-O-acetyl GD3), bovine buttermilk (mixture of 7-O-acetyl GD3, 9-O-acetyl GD3 and 7,9-di-O-acetyl GD3) and chemically modified GD3 from bovine brain (9-O-acetylated on the subterminal sialic acid). Only immunization with the buttermilk-derived O-acetyl GD3 preparation resulted in consistent production of IgM antibodies. However, the induced antibodies reacted with the immunogen and with 7-O-acetyl GD3 derived from hamster melanoma but not with 9-O-acetyl GD3 or human melanoma cells expressing 9-O-acetyl GD3 on their cell surface. In contrast, all O-acetyl GD3 derivatives used for immunization were recognized by murine MAbs that reacted with 9-O-acetyl GD3, and immunization of mice with buttermilk-derived O-acetyl GD3 resulted in the production of antibodies that reacted with human melanoma cells expressing 9-O-acetyl GD3. Apparently, the human and murine immune systems preferentially recognize different epitopes on these molecules.

Expression, purification, and characterization of human cytosolic serine hydroxymethyltransferase

A cDNA which codes for human cytosolic serine hydroxymethyltransferase (Garrow et al., 1993, J. Biol. Chem. 268, 11910-11916) has been cloned into a pT7-7 vector as a NdeI-EcoRI insert. HMS174 (de3) cells were transformed with this plasmid and, after induction with isopropyl thiogalactoside, expressed a catalytically active serine hydroxymethyltransferase. The enzyme was purified and shown to be the expressed human enzyme by N-terminal amino acid sequencing. About 225 mg of pure enzyme can be obtained from a 20-liter culture. Spectral characteristics of the bound pyridoxal phosphate were essentially identical to the spectral properties of rabbit cytosolic serine hydroxymethyltransferase. Kinetic constants for the natural substrates L-serine and tetrahydrofolate were also similar to the values obtained previously for the rabbit cytosolic enzyme.

Study on the effects of "foshousan" plus danshen in preventing IUGR rats with passive smoking from peroxidation in erythrocyte lipid

The pregnant rats with cigarette smoking exposure were used as the animal model for studying the pathogenesis of IUGR. The mechanism of preventing intrauterine growth retardation with "Foshousan" plus Danshen by protecting erythrocytes against lipid peroxidation damage was also preliminarily discussed. The erythrocyte membrane lipid peroxide content, erythrocyte SOD activities were detected by ultraviolet split-beam spectrophotometry and chemiluminescence technique. The results showed that the erythrocyte MDA levels and ratio of abnormal erythrocyte in model group were significantly higher than those in control group and treated group, and the fetal mean birth weight, erythrocyte SOD levels were all statistically significantly lower than those in control group and treated group. The fetal birth weight showed a significant positive correlation with SOD levels and a significant negative correlation with MDA level. The results suggest "Foshousan" plus Danshen can protect erythrocytes against lipid peroxidation damage, thus conserving the normal form, structure and function of erythrocytes, improving the uteroplacental blood flow and thereby increasing the fetal mean birth weight.

Changes in the nucleosomal structure of the Marek's disease virus genome in lymphoblastoid cell line MDCC-MSB1 induced by 5-azacytidine

Marek's disease virus (MDV) DNA in latently infected lymphoblastoid cell lines is considerably methylated. Treatment of the MDV-derived lymphoblastoid cell lines MDCC-MSB1 (MSB1) and MDCC-RP1 (RP1) with 5-azacytidine (5-AzC) results in hypomethylation of MDV DNA. An increase in mRNA from certain portions of MDV DNA, including the BamHI-H region, was observed in 5-AzC-treated MSB1 cells, but not in the agent-treated RP1 cells. After the treatment of cells with 5-AzC, a site hypersensitive to digestion with DNaseI appeared in the BamHI-H region of MDV DNA in MSB1 but not in RP1. These results suggested that the enhancement of mRNA synthesis by 5-AzC is associated with changes in the nucleosomal structure of MDV DNA in lymphoblastoid cell line MSB1.

Effect of thrombin on release of plasminogen activator inhibitor-1 from cultured primate arterial smooth muscle cells

Plasminogen activator inhibitor-1 (PAI-1) is the major inhibitor for plasmin formation promoted by tissue and urokinase plasminogen activators. The present study demonstrates that thrombin increase PAI-1 antigen, biological activity, and gene expression in cultured baboon aortic smooth muscle cells (BASMC). Thrombin elevates PAI-1 antigen in conditioned medium of BASMC within 10 min of the treatment, with the peak increase after 30 min of the treatment. Overexpression of PAI-1 gene was detected in the cultures exposed to thrombin for at least 60 min. PAI activity in conditioned medium increased in the cultures treated with thrombin for at least 4 h. The thrombin-induced early increase of PAI-1 antigen (up to 30 min of the stimulation) was blocked by hirudin (a specific inhibitor of thrombin), mimicked by trypsin and not suppressed by cycloheximide (a protein synthesis inhibitor). The majority of metabolically labeled PAI-1 associated with BASMC was present in extracellular matrix. The level of extracellular matrix-associated PAI-1 was reduced 40% by 30 min of thrombin treatment. Our results suggest that thrombin not only increases PAI-1 transcription but also proteolytically cleaves PAI-1 from the extracellular matrix of vascular SMC. PAI-1 released by thrombin from the extracellular matrix may not alter PAI activity in extracellular fluid but may reduce the storage of PAI-1 in the extracellular matrix of vascular smooth muscle cells.

Differential Effects of Glycosphingolipids n Protein Kinase C Activity in PC12D Pheochromocytoma Cells

Previous studies have shown that certain glycosphingolipids may function as modulators of protein kinase C (PKC) activity. To study the structure-activity relationship, we examined the effects of 17 gangliosides, 10 neutral glycolipids, as well as sulfatide, psychosine and ceramide on PKC activity in PC12D cells. Using an in vitro assay system, we found that all but one (GQ1b) ganglioside inhibited PKC activity at concentrations between 25 and 100 &mgr;M, and the potency was proportional to the number of sialic acid residues. However, at lower concentrations several gangliosides, including GM1 and LM1 behaved as mild activators of PKC activity. GQ1b had no effect within the range 0.1-10 &mgr;M, but acted as a mild activator of PKC activity at 25 &mgr;M. On the other hand, fucosyl-GM1 and GM1 containing blood group B determinant, which are abundant in PC12 cells, were potent inhibitors of PKC activity. Among the neutral glycosphingolipids tested, LacCer, Gb3, GalGb3, and GA1, all of which have a terminal galactose residue, were found to be ineffective or acted as mild activators of PKC activity. In contrast, GA2, Gb4 and Gb5 which have a terminal N-acetylgalactosamine residue, were potent inhibitors of the PKC activity. Thus, the terminal sugar residue may play a pivotal role in determining the effect of glycosphingolipids in modulating PKC activity. In addition, we also found that GalCer containing normal fatty acids acted as potent activators of PKC activity. Ceramide and GlcCer appeared to be ineffective in modulating PKC activity, wheras psychosine and sulfatides appeared to be inhibitory. We conclude that the carbohydrate head groups and the hydrophobic groups of gangliosides and neutral glycolipids may modulate the PKC system in unique manners, which may in turn affect various biological processes in the cell. Copyright 1994 S. Karger AG, Basel

Enhancement of mRNA synthesis from Marek's disease virus genome in the lymphoblastoid cell line, MDCC-MSB1, by 5-azacytidine

Marek's disease virus (MDV) DNA in latently infected lymphoblastoid cell lines is considerably methylated. A treatment of the MDV-derived lymphoblastoid cell line, MDCC-MSB1 (MSB1), with 5-azacytidine (5-AzC) resulted in a hypomethylation of MDV DNA and an increase in mRNA from certain portions of the MDV DNA. These results suggest methylation of MDV DNA as being one of the factors associated with a repression of transcription of MDV DNA in the lymphoblastoid cell line, MSB1.

GD3 vaccines for melanoma: superior immunogenicity of keyhole limpet hemocyanin conjugate vaccines

Cell surface gangliosides show altered patterns of expression as a consequence of malignant transformation and have therefore been of interest as potential targets for immunotherapy, including vaccine construction. One obstacle has been that some of the gangliosides that are overexpressed in human cancers are poorly immunogenic in humans. A case in point is GD3, a prominent ganglioside of human malignant melanoma. Using an approach that has been effective in the construction of bacterial carbohydrate vaccines, we have succeeded in increasing the immunogenicity of GD3 in the mouse by conjugating the ganglioside with immunogenic carriers. Several conjugation methods were used. The optimal procedure involved ozone cleavage of the double bond of GD3 in the ceramide backbone, introducing an aldehyde group, and coupling to aminolysyl groups of proteins by reductive amination. Conjugates were constructed with a synthetic multiple antigenic peptide expressing repeats of a malarial T-cell epitope, outer membrane proteins of Neisseria meningitidis, cationized bovine serum albumin, keyhole limpet hemocyanin, and polylysine. Mice immunized with these conjugates showed a stronger antibody response to GD3 than mice immunized with unconjugated GD3. The strongest response was observed in mice immunized with the keyhole limpet hemocyanin conjugate of the GD3 aldehyde derivative and the adjuvant QS-21. These mice showed not only a long-lasting high-titer IgM response but also a consistent high-titer IgG response (predominantly IgG1), indicating recruitment of T-cell help, although the titers of IgM and IgG antibodies following booster immunizations were not as high as they are in the response to classical T-cell-dependent antigens. This method is applicable to other gangliosides, and it may be useful in the construction of immunogenic ganglioside vaccines for the immunotherapy of human cancers expressing gangliosides on their cell surface.

Characterization of a hamster melanoma-associated ganglioside antigen as 7-O-acetylated disialoganglioside GD3

We previously reported a hamster animal model of melanoma in which the tumor tissue expresses gangliosides GM3, GD3, and O-acetyl GD3. This ganglioside pattern is similar to that in human melanomas (Ren, S., A. Slominski, and R. K. Yu. 1989 Cancer Res. 49: 7051). In this study, we isolated and purified these gangliosides using chloroform-methanol extraction, Folch partition, chromatographies on DEAE-Sephadex A-25, and Iatrobeads columns. The yields of gangliosides GM3, GD3, and O-acetyl GD3 were 44.1 mg, 19.6 mg, and 9 mg per 100 g of Ma melanotic melanoma tissues, respectively. The structures of these gangliosides were characterized by periodate oxidation, gas chromatographic (GC) analysis, fast-atom bombardment-mass spectrometry (FAB-MS), and nuclear magnetic resonance (NMR) studies. The structure of hamster melanoma O-acetyl GD3 is different from the 9-O-acetyl GD3 previously reported in human melanoma. The major fatty acids of this ganglioside are C16:0, C18:0, C20:0, C22:0, and C24:0 and the long-chain base is C18-sphingosine.

Activation of UDP-galactose:globotriaosylceramide alpha 1-3-galactosyltransferase during PC12D cell differentiation induced by galactosylceramide

We measured the activities of UDP-galactose:globotriaosylceramide alpha 1-3-galactosyltransferase (alpha-GalTase) and protein kinase C (PKC) in PC12D pheochromocytoma (PC12D) cells which were induced to differentiation by nerve growth factor (NGF), forskolin (FRK), staurosporine (STP), retinoic acid (RA), 2-chloroadenosine (ClAd), and/or galactosylceramide (GalCer). NGF, STP, FRK, and RA were found to be stimulators for the PKC activity, whereas ClAd appeared to be an inhibitor of the enzyme. At the concentration of 25 microM, GalCer having normal fatty acids was found to be a stimulator, whereas GalCer having hydroxy fatty acids was ineffective in modulating the PKC activity. Interestingly, all stimulators of PKC activities, including GalCer having normal fatty acids, appeared to be activators for the alpha-GalTase activity. On the other hand, GalCer having alpha-hydroxy fatty acids had no effect and ClAd was found to be a potent inhibitor for the alpha-GalTase activity. These data suggest that alpha-GalTase activity during PC12D cell differentiation may be regulated by a PKC-dependent process.

A dual fiber-optic sensor for oxygen and carbon dioxide

A newly designed dual fiber optical sensor is reported. It can sense both oxygen and carbon dioxide in gas phase with one sensing layer made of immobilizing fluorescent dyes Pyrene Butyric Acid (PBA) and Hydroxy Pyrene Trisulphonate (HPTS) in the same matrix. Its resolution is 0.1% for carbon dioxide and 0.5% for oxygen in clinical detecting range.

The major regulatory element upstream of the alpha-globin gene has classical and inducible enhancer activity

A major positive regulatory element has recently been identified 40 kb upstream from the human zeta 2-globin gene. This regulatory element increases the expression of a linked alpha-globin gene in mouse erythroleukemia cells and in transgenic mice. This element has been shown to share many of the structural and functional features of the locus control region (LCR) of the beta-globin gene cluster. We have examined the activity of a small fragment from this regulatory domain (alpha LCR) in a transient expression system. We show that this element is active as an enhancer in the erythroid environment of K562 cells. It is somewhat less effective as an enhancer in the nonerythroid environment of HeLa cells. This alpha LCR fragment does not exhibit promoter specificity because it can activate both the promoter of its endogenous target gene and the heterologous promoter of the SV40 early genes. Although the major activity of this element is mediated by its interaction with the promoter of the alpha-globin gene, some increase in activity is seen when structural elements from the 5' end of the alpha-globin gene are included with the target promoter. In addition, we show that the enhancing activity of the alpha LCR is potentiated by hemin-induction of K562 cells. Whereas phorbol esters that induce megakaryocytic differentiation of K562 cells markedly decrease alpha-globin messenger RNA accumulation, they do not seem to have a negative effect on the activity of the alpha LCR. These studies suggest a role for the alpha LCR in the basal activity of the alpha-globin gene in erythroid cells and in its increased expression seen with erythroid differentiation. The mechanism of negative regulation of alpha-globin gene expression in phorbol-differentiated K562 cells does not appear to be mediated through the action of the alpha LCR.

A study of the effect of magnetized water on enzyme activities by potentiometric enzyme electrode method

A very promising glutamate decarboxylase electrode, which has linear response range of 5.6 x 10(-5)-1.2 x 10(-2) mol/L. Nernstian slope of 50 mV/decade, detection limit of 3.2 x 10(-5) mol/L and response time less than 3 min, has been designed to observe and evaluate quantitatively the effect of magnetized water on enzyme activities by potentiometric enzyme electrode method. It was found that the activity of glutamate decarboxylase can increase by 30% in magnetized water. The mechanism of increased enzyme activity was discussed in the present paper. Such a new finding will probably lead to some new explanations for the physiological and biological mechanism of the effect of magnetized water on living organisms, thus providing a new approach to the study of the effect of magnetized water.

O-acetylated gangliosides in bovine buttermilk. Characterization of 7-O-acetyl, 9-O-acetyl, and 7,9-di-O-acetyl GD3

Three O-acetylated gangliosides, G1, G2, and G3, were purified from bovine buttermilk by using chloroform/methanol extraction, Folch partitioning, chromatography on DEAE-Sephadex A-25, and Iatrobeads columns. The final yields of gangliosides G1, G2, and G3 were 2 mg, 37 mg, and 40 mg per 1.7 kg of the buttermilk powder, respectively. On the basis of immunostaining on high performance thin layer chromatography with specific monoclonal antibodies, mild alkaline treatment, gas-liquid chromatographic analysis, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance studies, G1 and G2 are characterized as O-acetylated GD3 and G3 as O-acetylated GT3, and the structures of these gangliosides are as follows: [formula: see text] The major fatty acids of these gangliosides were C18:0, C22:0, C23:0, and C24:0, and the long chain base was C18-sphingosine.

A study of calcium ion-selective PVC membrane electrode based on neutral carrier N,n,n',n'-tetracyclo-3-oxapentanediamide (correction of oxapetanediamide)

A calcium ion-selective PVC membrane electrode based on neutral carrier n,n,n',n'-tetracyclohexyl-3-oxapetanediamide, using di-(2-ethylhexyl)phthalate as the plasticizer and potassium tetrakis (4-chlorophenyl) borate as the additive is reported in this paper. The ion selective membrane consists of 1 wt% of the Ca2+ selective ligand, 65 wt% of the plasticizer, 1 wt% of the additive and 33 wt% of poly (vinyl chloride) powder. The electrode has the linear response range of 2.0 x 10(-7)-10(-1) mol/L with the Nernstian slope of 28 mV/decade at 25 degrees C and the detection limit of 2.0 x 10(-8) mol/L. The response time of the calcium ion-selective electrode is as the concentration of calcium ion is rapidly shifted from 10(-5) to 10(-4) mol/L. The potential stability and reproducibility are good. The free calcium in blood serum was determined by the calcium ion-selective electrode with satisfactory results.

Serum SHBG levels during normal menstrual cycle and after insertion of levonorgestrel-releasing IUD

Daily serum sex hormone binding globulin (SHBG) levels were measured during normal ovulatory menstrual cycles in ten women between the ages of 23 and 34 by the method of precipitation with ammonium sulfate. The results showed that the mean SHBG levels in a cycle were quite different among individuals, but that the SHBG levels were constant during a certain menstrual cycle. Neither SHBG peaks on day LH-0 (52.64 +/- 19.89 nmol/L) (x +/- SD) nor the mean SHBG levels between the follicular phase (57.10 +/- 17.64 nmol/L) and luteal phase (64.75 +/- 23.42 nmol/L) show any significant differences. The correlations between the mean SHBG levels and the mean concentrations of progesterone (P), estradiol (E2) and androstenedione during the menstrual cycles were insignificant, whereas the mean SHBG levels during the follicular and luteal phase and on LH-0 day were significantly correlated with the mean concentrations of testosterone (t = 0.474; p less than 0.05). In ten women between the ages of 25 and 34, serum SHBG, E2, P, and levonorgestrel (LNG) levels were measured once on day 20-21 of the pretreatment cycle and 3 times/week during the 1st, and 2 times/week during the 6th treatment cycle after insertion of a levonorgestrel-releasing IUD (LNG-IUD). The mean value of SHBG in the pretreatment blood samples (62.09 +/- 23.09 nmol/L) was higher than that after insertion of the LNG-IUD (41.82 +/- 20.50 nmol/L), though the difference was not significant (p greater than 0.05). The correlation between LNG and SHBG was highly significant (r = 0.89, p less than 0.01). The significance of this correlation and the degree of suppression of ovarian function are discussed.

Identification of male-factor semen samples prior to insemination and in vitro fertilization

Semen analyses carried out as part of the clinical in vitro fertilization or intrauterine insemination protocols provide important information that determine the type of clinical treatment of the male partner and the sperm processing method. It is postulated that the sperm of male-factor patients cannot survive hypoosmotic stress conditions because of defective sperm membrane function. To test this, 0.1 ml of semen from each of 102 patients was placed in 1.0 ml of 150 mosmol/liter eosin citrate fructose solution and incubated for 30 min at 37 degrees C. The percentage viability of the sperm cells was then determined. The results indicated that patients with two or more abnormal semen parameters had a significantly lower percentage viability while in the hypoosmotic solution (40.6 +/- 4.7%), in contrast to non-male-factor patients (69.0 +/- 1.6%). Donor sperm (N = 32) serving as controls (73.3 +/- 2.1%) had a viability in hypoosmotic solution similar to that of non-male-factor patients. The data suggest that sperm of male-factor patients are less able to survive the hypoosmotic stress conditions as shown by the percentage viability in hypoosmotic solution and emphasize the importance of using less stressful sperm processing methods for in vitro fertilization or insemination in these patients.

[Role of a virus in hemorrhagic pancreatitis and the therapeutic effect of rhubarb]

The living measles vaccine was injected into both of the main pancreatic duct and the ear vein of the rabbits in the model group. The serum amylase was significantly higher than that of the control saline group (P less than 0.001 after 24h; P less than 0.05 after 48h). The aggregation function of platelets were increased after 24h(P less than 0.01, P less than 0.01) and 48h (P less than 0.01, P less than 0.05) as compared with both two control groups. The blood stasis and hemorrhage of pancreases were observed in the model group. In the treatment group with Rhubarb the increase of serum amylase was much less marked than the control (P less than 0.001 after 24h, P less than 0.05 after 48h). The platelet aggregation reactivity was inhibited (P less than 0.01 after 24h, P less than 0.05 after 48h). The blood stasis and hemorrhage of pancreases were less evident. The results suggested that: (1) the virus may be one of pathogenetic factor of the hemorrhagic pancreatitis; (2) the rhubarb was effective in the treatment of hemorrhagic pancreatitis under our experimental conditions.